"Rajan" <[email protected]> wrote in message
news:[email protected]..
>
> Hi all!
> I am a newbie to DSP. I have some basic questions. I will really
> appreciate if someone answers them.
>
> 1. Is it logical to perform 1024 point FFT on a vector of size less than
> 1024 (say 150) in MATLAB ?
> 2. If yes, then -does MATLAB perform zero padding automatically in above
> case or do we need to do it manually ?
> 3. what kind of output will it give ?

1. Maybe, if that's what you want to do.
It will take longer than computing an fft over just 150 points.
The results will be an interpolated version of an fft that is 150 points but
add really no new information. So, the apparent increased resolution is a
bit illusory.

2. It depends. If you use fft(x) then no. If you use fft(x,n) then yes.

3. A complex vector of the length of x in the first case. A complex vector
of length n in the second case.